A Friend Indeed: Hydraulic Fluid That’s Safe for the Planet

By Benjamin Garmier, Vice President, Renewable Lubricants Inc.

As companies develop alternates to traditional lubes and greases, there is often confusion about the terms “environmentally friendly” and “food grade.”  Formulations that meet the criteria for one don’t necessarily hit all the notes for the other. The Environmental Protection Agency defines EAL – environmentally acceptable lubricants –according to three criteria: biodegradability, toxicity to marine and aquatic life, and bioaccumulation. This article looks at how Renewable Lubricants’ Bio-Food Grade Hydraulic Fluid is both environmentally friendly and food grade. 

Food grade

According to the National Sanitation Foundation, to be registered as a lubricant that allows for incidental food contact, the product must be odorless, colorless, and tasteless. It must not contain more than
10 parts per million of lubrication base oils (for example, mineral oil), and it must be registered as H1 or certified to ISO 21469. Additionally, it must be manufactured from ingredients, chemical compounds, or additives allowed by the FDA’s Code of Federal Regulations Title 21, Section 178.3570. Or it must be manufactured from ingredients designated GRAS – generally recognized as safe.

Feedstocks

Feedstock – the materials from which the lubricant is made – plays a big part in determining whether a hydraulic fluid meets the EAL standard. Biobased products, especially those made from vegetable oils, are inherently safer for the environment than petroleum-based products, which is just one reason for their increasing popularity. Formulations that use food-grade edible oils along with vegetable-based oils that are further processed into a biosynthetic to enhance their lubricity and protective properties are not only safer for the environment than petroleum-based products, they are also safer for employees. Petroleum-based products can be caustic and harmful in contact with skin, whereas biobased products generally pose no problems with incidental skin contact.

Renewable Lubricants has developed a proprietary and patented technology using high oleic base stocks (HOBS), which are agricultural biobased oils. Incorporating the super high viscosity index of the Stabilized HOBS into the formula increases the viscosity past synthetic levels. The super high viscosity index of HOBS naturally improves the thermal shear stability of the formula and increases load capacity. The low volatility of HOBS increases the flash and fires safety feature of the formula, making it safer for employees. 

These patented biobased hydraulic fluids are formulated to perform in high- and low-pressure hydraulic systems that require anti-wear, anti-rust, anti-oxidation, anti-foam, and demulsibility properties. They provide improved performance in oxidation stability over standard plant/vegetable/HETG and unsaturated HEES type fluids. Formulated to provide a longer seal life with reduced oil leakage, Bio-Food Grade Hydraulic Fluid meets or exceeds high-pressure pump requirements. 

The fluid is highly inhibited against moisture and rusting in both fresh and sea water, and it passes A and B sequences of the ASTM D-665 turbine oil rust test. Formulated to provide a longer seal life with reduced oil leakage, the zinc-free product is ideal for vane, piston, and gear-type pumps. It has shown excellent anti-wear performance in the ASTM D-4172 four-ball wear test. The anti-wear performance meets and exceeds requirements for Vickers M-2950-S (35VQ-25) and I-286-S (V-104C), Rexroth, U.S. Steel 126, 136, and 127, and DIN51524 Part 2. The fluid also meets the requirements for ashless GL-1 an GL-2 gear oils in reduction units and gear sets where EP gear oils are not recommended.

To ensure performance and long life, Renewable Lubricants developed the stringent IsoGreen filtration standard, which meets or exceeds the Rexroth pump guidelines for hydraulic fluids. 

Biodegradable

Biodegradability is broken down into two classes – readily biodegradable and inherently biodegradable – based on how much of the product breaks down within a set timeframe. Readily biodegradable products break down by 60% or more within a 28-day period. If they do not meet this criterion, if they fall, for example, between 20% and 59% within 28 days, then they are classified as inherently biodegradable. Most industrial applications strive for readily biodegradable products, but the classifications are not well understood or explained. Some products that are inherently biodegradable are merely marked “biodegradable” without explanation. When in doubt, ask for the details from the manufacturer or distribution channel partner before specifying a product based on its biodegradability. Bio-Food Grade Hydraulic Fluid is readily biodegradable. 

Toxicity

The EPA and the U.S. Fish and Wildlife Service base toxicity on how much of a chemical (with concentrations measured in parts per million) is present before it becomes harmful to plants (algae) and fish. There are different values for each. For acute toxicity for algae, EC50 in the concentration of test substance that results in a 50% reduction in either growth or growth rate relative to the control within 72-hours of exposure. The acute toxicity of fish is expressed as the median lethal concentration (LC50), which is the concentration in water that kills 50% of a test batch of fish within 96 hours of continuous exposure. Bio-Food Grade Hydraulic Fluid exceeds the acute toxicity levels (LC50/EC50 > 1,000 ppm) adopted by the U.S. Fish and Wildlife Service and the EPA. 

With oxidation performance (biodegradability and toxicity) comparable to full synthetics, this is one of the safest hydraulic fluids for the environment and the only one that is food grade. In addition to use on food processing equipment, Bio-Food Grade Hydraulic Fluid is ideal for use in environmentally sensitive areas such as marine environments, aboard fishing vessels, and in agriculture, especially in harvesting of grains as well as working in and around fruit farms and processing facilities.  

Bioaccumulation

Bioaccumulation is the buildup of foreign chemicals within the tissues of living organisms over time. Heavy metals like zinc, cadmium, and others either do not break down or do so very slowly. When they enter a water source, they are ingested by smaller fish, which are food sources for larger fish, until the fish become food sources for humans. 

Renewable Lubricants products are formulated with no zinc or other heavy metals, so there are no bioaccumulation worries. They are also free of volatile organic compounds, so they are safe for workers and the environment. Made from renewable agricultural biobased resources, they are sustainable as well. •

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